Re: Clock Tolerance and WAN PHY
I agree that this is an excellent and simple addition.
Osamu ISHIDA wrote:
> Correction to my previous reflector note.
>
> At 23:55 01/01/27 +0900, Osamu ISHIDA wrote:
>
>> Instead, I recommend vendors to support one more MAC rate of
>> 9.61 Gb/s. This will allow us to map 64/66-encoded LAN-PHY signals
>> into OPU2 by simply deleting the inter-frame Idles.
>>
>> (9.61 Gb/s = 9 953 280 kbit/s * 64/66 * 237/238)
>
>
> The recommended MAC rate for the OTN should be 9.69 Gb/s.
> (9.69 Gb/s = 9 953 280 kbit/s * 64/66 * 238/237)
>
> Best Regards,
> Osamu
>
>
> At 23:55 01/01/27 +0900, Osamu ISHIDA wrote:
>
>> Hi Gary, and All,
>>
>> Here is the clock and its tolerance of the client signal for G.709 OTN
>> (Optical Transport Network) that will be approved by ITU-T (Feb 2001).
>> It does not support the direct mapping of 10.3 Gb/s LAN-PHY signal.
>>
>> a) it accepts OC-192c (9 953 280 kbit/s) format with approximately
>> +/- 45 ppm clock tolerance (CBR10G asynchronous mapping into OPU2)
>> OPU2: Optical Channel Payload Unit 2 (OPU1 is for 2.5G, OPU3 is for 40G)
>>
>> b) it accepts OC-192c (9 953 280 kbit/s) with +/- 20 ppm tolerance
>> (CBR10G bit-synchronous mapping into OPU2)
>>
>> c) it accepts bit stream (approximately 9 995 276.962 kbit/s) with
>> +/- 20 ppm tolerance
>> (Mapping of non-specific client bit stream into OPU2)
>>
>> The possible directions I see in the 802.3ae WAN-PHY are;
>>
>> 1) no change.
>> WAN-PHY signal with +/- 100 ppm tolerance will be accommodated into
>> OTN by ELTE (i.e. by using SONET pointer manipulation mechanism).
>>
>> 2) reduce the WAN-PHY clock tolerance to +/- 45ppm.
>> This will allow us to map the WAN-PHY signal into OPU2 directly if
>> the OTN edge equipment supports asynchronous mapping (i.e. byte
>> stuffing mechanism similar to that using the SONET H3 byte).
>>
>> 3) reduce the WAN-PHY clock tolerance to +/- 20ppm.
>> This will allow us to map the WAN-PHY signal into OPU2 directly
>> even if the OTN edge equipment only supports bit-synchronous mapping
>> (i.e. WAN-PHY clock is used in the OTN signal as well).
>>
>> I have no preference in the above three directions since my own
>> interest is to have 9.29 Gb/s MAC rate from the LAN Equipment.
>> Instead, I recommend vendors to support one more MAC rate of
>> 9.61 Gb/s. This will allow us to map 64/66-encoded LAN-PHY signals
>> into OPU2 by simply deleting the inter-frame Idles.
>>
>> (9.61 Gb/s = 9 953 280 kbit/s * 64/66 * 237/238)
>>
>> Best Regards,
>> Osamu
>
>
> ---------------------------------------
> Osamu Ishida,ishida@exa.onlab.ntt.co.jp
> NTT Network Innovation Laboratories
> TEL:+81-468-59-3263 FAX:+81-468-55-1282
> ---------------------------------------
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Dr. Gary A. Nelson
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